Antibody fingerprinting is a novel identification system based on antibodies present in body fluids. The technique has advantages over DNA fingerprinting in terms of speed (hours vs weeks), simplicity (no special equipment or training necessary), and sensitivity (0.1-10. ul vs greater than 100 ul required). Individual humans and lower animals have unique antibody fingerprints. The antibody resemble bar codes similar to those found on supermarket products, and are stable for at least a decade, probably longer. The assay is a dipstick assay based on immunoblotting (Western blotting). The method has applications in forensic medicine, where the identity of an individual may be discovered by analyzing blood or semen stains. The technique, when coupled to a computerized registry, may prove useful in identifying animals, such as race horses or zoo animals. Possible future uses include identifying handicapped persons or found children. The goals of the project are to determine (1) whether antibody fingerprinting may be performed with body fluids other than blood that contain antibodies, such as saliva, tears, or perspiration; (2) whether the individual-specific antibodies that are detected in the assay are functionally stable under various conditions of storage; (3) whether antibody fingerprints are stable during short term illnesses, such as the common cold; and (4) whether newborn animals and humans have the same antibody fingerprint as their mother, and (5) whether non-radioactive detectors may be used in the assay.